I would like to know please how much physical work is involved when a BT line goes through the ADSL stages. Perhaps things are different with the LLU side but take this as being "normal" ISP goings on.
1. I take it there's a "card" or circuit associated with the phone number so does anything get added onto this when ADSL is first set up?
2. If the first ADSL was low speed <8meg what happens about going onto the 20meg or 21CN type of rate or making a change of ISP, any change again of card or cabling?
3. If any physical cards or the like get involved what potential problems might there be, not just about the ADSL but releated to the voice line?